170 or 175 mm crank...
 

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[Closed] 170 or 175 mm cranks - will I notice the difference?

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Building a 17.5 inch enduro machine, 26". Guessing 170 will be better for avoiding rock strikes on paper but will I really notice the difference? I'm on a budget and 175mm are a lot more readily available cheaply.

What do you think?


 
Posted : 03/03/2015 4:42 pm
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I don't, personally. I went down to 165 and I could feel that, but mostly just from the narrow stance rather than pedalling or rock strikes or whatever, I think basically I use whatever clearance I have rather than really noticing whether I have less or more...


 
Posted : 03/03/2015 4:46 pm
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Personally, my knees notice the difference and I always run 170mm now (MTB and road). I'm 5'11 with 32" inside leg if that's any help for reference.


 
Posted : 03/03/2015 4:52 pm
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felt the difference for me as well "30 leg.. from 175 to 170.. less rock strikes now.. but for some reason I like pedaling in long uphills on 175


 
Posted : 03/03/2015 5:07 pm
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I don't know - I certainly can!


 
Posted : 03/03/2015 5:12 pm
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Me too.

175 - hurty knees.
170 - non hurty knees.


 
Posted : 03/03/2015 5:14 pm
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I switched from 175mm cranks to 170mm cranks.

I cant tell the difference in the crank length in terms of pedalling etc, it feels exactly the same to me.

But the shorter cranks do make a significant difference in terms of reducing pedal strikes, with the old 175mm cranks I was bashing them a fair bit, now that I've swapped to 170mm cranks the bashing has substantially reduced.


 
Posted : 03/03/2015 6:06 pm
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5mm makes **** all difference to pedal clearance.
5mm makes a slight difference to comfortable cadence speed.
5mm makes a bigger difference to knee comfort.

I do notice all of the above, no idea if OP will.


 
Posted : 03/03/2015 8:05 pm
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5mm makes **** all difference to pedal clearance.

And there was me thinking it made 5mm difference? Or indeed the difference between smacking hard into something and missing it by a few mm...


 
Posted : 03/03/2015 8:08 pm
 duir
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I found that 5mm made all the difference in the world on my Nicolai for pedal strikes. Went from 175-170mm, 6' 33" inside leg. Didn't notice any difference otherwise.


 
Posted : 03/03/2015 8:09 pm
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Don't argue with gw.

We must all be wrong if he says so.


 
Posted : 03/03/2015 8:18 pm
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You either can't time pedal strokes very well or you learn how.. guess some of you eventually learned.


 
Posted : 03/03/2015 8:24 pm
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I don't even k is what length my cranks are. I used to have a set of 165 cranks which I liked on an old bike. But I expect the current bike is 170 or 175 as that's what seems to be specced nowadays. Not really noticed.
There was an interview with a mechanic or sports scientist with a big roadie team and when asked how they calculate crank length (as they calculate everything else about sizing) they said it basically made little difference and let the riders have what they wanted.
Think the it was from a link on an earlier post on STW


 
Posted : 03/03/2015 9:24 pm
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Excuse the slight hijack, but why would a shorter crank arm be better for knees?


 
Posted : 03/03/2015 9:48 pm
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170mm on all my bikes, road and mtb. I noticed a world of difference on my old MTB re. pedal strikes. It did have a stupidly low BB though.


 
Posted : 03/03/2015 9:49 pm

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